One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,3)(5,6,9,12)(7,11,8,10)(13,14,17,20)(15,22,21,18)(16,23,24,28)(19,26,27,25)(5,6)(7,10)(8,11)(9,12)(13,15)(14,18)(16,23)(17,21)(19,26)(20,22)(24,28)(25,27) involution — undirected(5,7,9,8)(6,10,12,11)(13,16,17,24)(14,19,20,27)(15,23,21,28)(18,26,22,25)(5,7,9,8)(6,11,12,10)(13,14)(15,22)(16,19)(17,20)(18,21)(23,25)(24,27)(26,28)(1,3,4,2)(5,8,9,7)(6,11,12,10)(14,20)(15,21)(19,27)(23,28)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.